Fiber matrix for a geometric morphing wing

ABSTRACT

An airfoil member ( 14 ) includes a geometric morphing device ( 18 ). The geometric morphing device ( 18 ) has an inflatable member ( 30 ). The inflatable member ( 30 ) has an exterior wall ( 32 ) and multiple inflated states. The exterior wall ( 32 ) includes a layer with one or more fibers embedded therein. The exterior wall ( 32 ) controls size, shape, and expansion ability of the geometric morphing device ( 18 ).

RELATED APPLICATION

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 10/268,558, filed on Oct. 10, 2002, entitled“Geometric Morphing Wing with Layers” and U.S. patent application Ser.No. 10/268,574, filed on Oct. 10, 2002, entitled “Geometric MorphingWing”, which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates generally to aeronautical vehicle systems,and more particularly, to an apparatus, system, and method of alteringthe size and shape of an airfoil member.

BACKGROUND OF THE INVENTION

Airfoil members such as wings, horizontal and vertical stabilizers,conards, rotor blades, etc. are limited in ability to change their sizesand shapes so as to alter surfaces of the airfoil member and beadaptable to multiple flight conditions of a flight envelope.

Currently, airfoil member surfaces of an aircraft can be modified to acertain extent by various devices for improved flight characteristicssuch as during low-speed handling, autopilot maneuvering, or forhigh-speed aerodynamics. Aircraft that need to operate in severalperformance environments, however, often must compromise flightperformance by using airfoil members that provide suitablecharacteristics in multiple environments rather than using airfoilmembers that are specifically designed for a particular flightsituation.

Aircraft designs known today utilize a variety of airfoil member surfacemodifying devices such as, flaps, slats, flaperons, ailerons, splitailerons, or other leading or trailing edge devices known in the art, toprovide control forces and moments during flight. Also, other devicessuch as micro flow devices, zero mass jets, and the like are used tocontrol the airflow over the airfoil member to further control forcesand moments. Additionally, devices such as smart materials are used toslightly modify shape of the airfoil member itself or of the airfoilmember surface modifying devices. However, all of there devices arelimited in their ability to alter shape, size, and characteristics ofthe airfoil member; the airfoil member devices typically only modify asingle aspect of the airfoil member, minimally affect airflow, orslightly modify shape of the airfoil member. Furthermore, all of theabove-stated devices tend to use mechanical actuators and othermechanical components to perform minor changes in an airfoil surface.

Military aircraft have utilized mechanically swept wings for improvedaerodynamics during high-speed flight. These mechanical surface systems,however, typically only provide a very limited ability to affect airfoilmember shape and aerodynamic flight characteristics of the aircraft. Thelimited ability to significantly change airfoil member shape can resultin an airfoil member that is particularly suitable for only a limitedrange of a flight envelope.

It is therefore desirable to provide an airfoil member and an airfoilmember altering system that significantly modifies shape and size of theairfoil member and at the same time provides an airfoil member withincreased adaptability for various flight conditions throughout a flightenvelope. An airfoil member with improved adaptability may potentiallybe capable of supporting greater payloads at lower speeds and duringtake-off, better lift characteristics at high speed, and increasedflight range. It is also desirable that the airfoil member has arelatively simple design, is relatively easy to manufacture, and iseconomically feasible.

SUMMARY OF THE INVENTION

The present invention provides an apparatus, system, and method ofaltering the size and shape of an airfoil member. The airfoil memberincludes a geometric morphing device, which has an inflatable member.The inflatable member has an exterior wall and multiple inflated states.The exterior wall includes a layer with one or more fibers embeddedtherein. The exterior wall controls size, shape, and expansion abilityof the geometric morphing device.

The present invention has several advantages over existing airfoilmember altering devices. One advantage is that the invention provides anairfoil member that is capable of significantly changing its size andshape. Versatility of the present invention also allows shape of theairfoil member to alter in compound manners. The ability tosignificantly change in size and shape provides increase applicationversatility and increased flight control throughout a flight envelope.

Another advantage of the present invention is that it provides improvedadaptability. The present invention provides improved flightcharacteristics including supporting greater payloads at lower speedsand during take-off, better lift at higher speeds, and increased flightrange in comparison with traditional airfoil member altering devicesthat are limited in one or more of the above-stated characteristics.

Moreover, the present invention provides a simplified configuration forthe exterior wall of the inflatable member for ease ofmanufacturability, and reduced costs. The simplified configuration haslow bending stiffness, unlike conventional wing structures, allowinggeometry thereof to be easily altered with change in fiber angle.

The present invention itself, together with further objects andattendant advantages, will be best understood by reference to thefollowing detailed description, taken in conjunction with theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective and schematic view of an aircraft that isutilizing an airfoil member altering system in accordance with anembodiment of the present invention;

FIG. 2 is a cross-sectional side view of a geometric morphing devicehaving multiple inflatable members in accordance with an embodiment ofthe present invention;

FIG. 3 is a perspective view of an airfoil member having a geometricmorphing device stretched significantly along a span axis in accordancewith another embodiment of the present invention;

FIG. 4 is a perspective view of an airfoil member having a geometricmorphing device stretched significantly along a chord axis in accordancewith another embodiment of the present invention;

FIG. 5 is a quarter cross-sectional view of a geometric morphing deviceincluding multiple layers in accordance with another embodiment of thepresent invention;

FIG. 6 is a logic flow diagram illustrating a method of forming ageometric morphing device in accordance with an embodiment of thepresent invention;

FIG. 7 is a logic flow diagram illustrating a method of altering anairfoil member in accordance with an embodiment of the presentinvention; and

FIG. 8 is a quarter cross-sectional view of a geometric morphing deviceincluding a single layer having an embedded fiber mesh in accordancewith another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In each of the following figures, the same reference numerals are usedto refer to the same components. While the present invention isdescribed with respect to an apparatus, system, and method of alteringsize and shape of an airfoil member, the present invention may beadapted for various applications including ground-based vehicles,aeronautical vehicles including fixed wing and rotary wing aircraft,watercraft, and other applications known in the art that require the useof airfoil members. The present invention may be applied to verticalstabilizers to increase control at lower speeds and to decrease drag athigher speeds, to winglets for modifying flight speed, and as well as tohorizontal and conard surfaces. The present invention may be applied toflaps and ailerons to modify shape of an airfoil member. The presentinvention may also be used to modify flight control by changing the sizeand shape of a first wing in a first manner and by maintaining a secondwing in a current state or by changing the size and shape of the secondwing in a second manner, thus causing rolling, pitching, or yawingmoments.

In the following description, various operating parameters andcomponents are described for one constructed embodiment. These specificparameters and components are included as examples and are not meant tobe limiting.

Also, in the following description the term “morphing” refers to abilityof an object or device to change. The term “geometric morphing device”refers to the ability of a device to change in size and shape. Forexample, an airfoil member of the present invention is capable ofchanging in size and shape such that span, chord, and camber of theairfoil member are adjustable.

Referring now to FIG. 1, a perspective and schematic view of an aircraft10 that is utilizing an airfoil member altering system 12 in accordancewith an embodiment of the present invention is shown. The airfoil system12 includes an airfoil member 14 having a rigid member 16 and ageometric morphing device 18 that is adjustable in both size and shape.The morphing device 18 is fluidically coupled to a pump 20, via tubes22, which transfer fluid between the tubes 22 and the morphing device18. A controller 24 is electrically coupled to the pump 20, to asolenoid 26, and to an inflatable member pressure sensor 27. Thecontroller 24 is also electrically coupled to multiple aircraft devicesincluding vehicle performance sensors 28 and aircraft control inceptors(not shown). The controller 24 may be coupled to other aircraft devicesand may determine positions of the control inceptors for constantvehicle operating states such as a constant altitude mode or constantvelocity mode. The controller 28 determines appropriate size and shapeof the morphing device 18 for multiple flight conditions throughout aflight envelope. Of course, mechanical devices may also be used tomodify the geometric morphing device 18.

Although in FIG. 1, for simplicity, a single geometric morphing device18 is shown for a single airfoil member 14 and although a singleinflatable member 30 is shown for the morphing device 18, the presentinvention may have multiple airfoil members each of which havingmultiple morphing devices, and may have multiple inflatable members permorphing device.

The morphing device 18 includes an inflatable member 30, which mayoverlap the rigid member 16. Although, a single rigid member is shownmultiple rigid members may be utilized and may exist within theinflatable member 30. The inflatable member 30 may inflate in aunilateral direction or in multiple directions. The inflatable member 30has an exterior wall 32 and multiple inflated states. A fiber mesh 34,having multiple fibers 36, is coupled to the exterior wall 32 andchanges in shape according to angles of the fibers 36, hereinafterreferred to as fiber angle. The morphing device 18 is adjustable in sizeand shape by changing inflated state of the inflatable member 30,according to fiber angle. The shape and size of the morphing device 18is not limited to changing in a single direction and may change incompound directions, which will become more apparent with the followingdescription.

The inflatable member 18 is pressurized by fluid, which may be in theform of atmospheric air, hydrogen, or other lightweight liquid orgaseous fluid, or combination thereof. The inflatable member 18 may havemultiple chambers as to minimize effects of punctures or leaks in themember 18. The inflatable member 18 may be used to dampen or absorb airturbulence.

The fiber mesh 34 is a braided/overlay of the multiple fibers 36 thatprovides rigidity to the morphing device 18. The fiber mesh 34 may beformed of steel fibers, composite fibers such as kevlar or zylon,aluminum fibers, or other fibers known in the art with high tensilestrength. The fiber mesh 34 may also have varying tensile strengthacross the morphing device 18. The fiber mesh 34 may be coupled withinthe exterior wall 32, as shown, or may be part of a geometric morphingsupport layer 38 that encapsulates an exterior wall 32″, as best seen inFIGS. 2 and 3.

The exterior wall 32 and the support layer 38 are continuously intension to maintain appropriate shape and rigidity of the airfoil member14 for various flight conditions. The exterior wall 32 is formed ofelastomeric material or a combination of elastomeric material and afiber material as in fiber mesh 34. The support layer 38 is formed ofelastomeric and fiber material as in fiber mesh 34. The fiber mesh 34may be embedded within the exterior wall 32 or may be embedded withinthe support layer 38.

The fiber mesh 34 may have a uniform, patterned, diverse, or varyingfiber angle distribution. Maximum width of the morphing device isdependent upon density distribution of the fibers 36. Also, the densityof the fibers 36 or the number of fibers 36 per square inch area of themorphing device 18 may be diverse. For example, the number of fibers 36may be greater near a trailing edge 40 of the airfoil member 14 and lessnear a leading edge 42 of the airfoil member 14 such that the inflatablemember 30 expands more near the leading edge 42 than near the trailingedge 40. The density of the fibers 36 per square inch area may vary inorder to provide varying degrees of rigidity and expansion for differentportions of the morphing device 18. The morphing device 18 may havemultiple drop-off areas whereby the number of fibers 36 per square inchin a particular direction decreases. In combination, for example, thefiber mesh 34 may have multiple stations 44 having varying numbers offibers per square inch and varying angles between fibers for a specificinflated state.

The morphing device 18 has a pair of supporting spars 46 and may alsoinclude expandable spars and ribs. Although, the supporting spars 46 arelocated near the trailing edge 40 and the leading edge 42 they may belocated elsewhere. For further explanation on expandable spars, see U.S.patent application entitled “Geometric Morphing Wing with ExpandableSpars” having Attorney Docket Number 02-0257. Ribs may be used to retainshape of the morphing device when the inflatable member 30 is deflated.Any number of spars or ribs may be used.

The controller 24 is preferably microprocessor based such as a computerhaving a central processing unit, memory (RAM and/or ROM), andassociated input and output buses. The controller 24 may be a portion ofa central main control unit, a flight controller, or may be astand-alone controller as shown.

The vehicle performance sensors 28 may include vehicle external airpressure sensors, velocity sensors, acceleration sensors, momentsensors, altitude sensors, inflatable member pressure sensors, or othersensors known in the art. The vehicle performance sensors 28 maydetermine a current velocity and acceleration of the aircraft 10, aswell as determining a current moment about a heading or z-axis, a pitchor x-axis, and a roll or y-axis.

Referring now to FIG. 2, a cross-sectional side view of a geometricmorphing device 18′ having multiple inflatable members 30′ in accordancewith an embodiment of the present invention is shown. Distribution andquantity of inflatable members 30′, fiber angle distribution, and fiberdensity separately or in combination may also be varied throughout themorphing device 18′ so as to allow for change in camber of the morphingdevice 18′. In one embodiment of the present invention, an upper portion50 of the morphing device 18′ is altered differently than a lowerportion 52 of the morphing device 18′, by applying an increased amountof pressure in an upper inflatable member 54, thus adjusting camber.Note an airfoil member that has ability to be altered in camber may beutilized on an aircraft that transitions quickly from low travelingspeeds to high traveling speeds.

Referring now to FIGS. 3 and 4, perspective views of an airfoil member14′ having a geometric morphing device 18″ stretched significantly alonga span axis, as represented by arrows 60, and significantly along achord axis, as represented by 62 is shown.

The morphing device 18″ has multiple span, chord, and cambercombinational modes corresponding to multiple flight conditions. Themorphing device 18″ has approximately a 200% difference in span lengthbetween a minimum span state to a maximum span state and also hasapproximately a 200% difference in chord length between a minimum chordstate and a maximum chord state. The fiber angles 64 of the fiber mesh34 may vary between approximately 0° in a first fully stretched state,corresponding to a maximum span length of said morphing device, andapproximately 180° in a second fully stretched state, corresponding to amaximum chord length of said morphing device 18″.

In FIG. 3, the morphing device 18″ is shown such that the fiber mesh 34is stretched significantly along the span axis and the fibers 36 are atan angle of approximately 10° relative to the x-axis. In FIG. 4, themorphing device 18″ is shown such that the fiber mesh 34 is stretchedsignificantly along the chord axis and the fibers 36 are at an angle ofapproximately 80° relative to the x-axis.

Although the fibers 36 are shown having a uniform distribution acrossthe morphing device 18″ and having a uniform number of fibers 36 persquare inch the fibers 36 as stated above may have varying distributionsand distribution densities.

Referring now to FIG. 5, a sample quarter cross-sectional view of ageometric morphing device 18′″ including multiple layers 70 inaccordance with another embodiment of the present invention is shown.The geometric morphing device 18′″, as shown, includes an innerelastomer layer 72, which may in itself be an inflatable member. A firstfiber layer 74 having a first fiber mesh 75 with a first fiber pattern76 is coupled to the inner elastomer layer 72. A first elastomer withfiber layer 77 having a second fiber mesh 78 and a second fiber pattern79 is coupled to the first fiber layer 74. A second fiber layer 80having a third fiber mesh 81 and a third fiber pattern 82 is coupled tothe first elastomer with fiber layer 77. A second elastomer with fiberlayer 83 having a fourth fiber mesh 84 with a forth fiber pattern 85 iscoupled to the second fiber layer 80. A third fiber layer 86 having afifth fiber mesh 87 and a fifth fiber pattern 88 is coupled to thesecond elastomer with fiber layer 83. An outer elastomer layer 89 iscoupled to the third fiber layer 86 and provides a smooth outer shell.The above stated layers form a matrix 90. Of course, there may be anynumber of elastomer layers, fiber layers, and elastomer with fiberlayers. Also, each layer 70 may be of various size and shape and be ofvarious material as stated herein and as known in the art.

The fiber layers 74, 80, and 86 may have varying fiber meshes withvarying fiber angles between fibers. The fiber angles of the fiberlayers 74, 80, and 86 control shaping of the geometric morphing device18′″. Each fiber mesh of the fiber layers 74, 80, and 86 may haveuniform, identical, varying, or multiple fiber patterns or a combinationthereof.

The elastomer with fiber layers 77 and 83 have fiber meshes 78 and 84that may be embedded within elastomer material of the layers 77 and 83,as shown. The fiber meshes 75, 78, 81, 84 and 87 provide stiffness tomaintain shape of the layers 74, 77, 80, 83, and 86 and of the geometricmorphing device 18′″.

Having multiple layers with varying fiber matrices, fiber patterns, andlayer distributions increase versatility in controlling size, shape, andexpansion ability of the geometric morphing device 18′.

Referring now to FIG. 6, a logic flow diagram illustrating a method offorming a geometric morphing device in accordance with an embodiment ofthe present invention is shown.

In step 100, intended flight conditions for a flight envelope of anaircraft of interest are determined. Generally, an aircraft has intendeduse and a corresponding flight envelope. The present invention may beapplied in development of an aircraft for a specific flight envelope butfortunately, due to the versatility of the present invention, may alsobe designed to operate in multiple flight envelopes or to operate inranges outside of the intended use flight envelope.

In step 102, inflatable member distributions and characteristics aredetermined including quantity, material type, size, shape, and otherinflatable member characteristics known in the art.

In step 104, when the geometric morphing device is to have multiplelayers, layer distributions are determined for the layers. The layerdistributions may include number of layers, types of layers,distribution of the layers or in other words where each layer is coupledrelative to each and every other layer, and other layer distributionsknown in the art.

In step 106, fiber angle distributions are determined along a chord axisor a span axis including determining minimum and maximum angles forvarious flight conditions. Fibers may be preset to have varying fiberangles for a particular inflated state.

In step 108, fiber characteristics are determined including fiberdensity, fiber material, fiber thickness, and fiber distribution tosatisfy flight envelopes of interest such that a morphing device may bealtered into multiple shapes, each shape corresponding to a particularflight condition. Fiber taper or drop-off is also determined formultiple stations.

When the geometric morphing device 18 has multiple layers 70, steps 106and 108 are performed for each layer 70. Fiber angle distributions andfiber characteristics may be determined relative to each other and as aconglomerate so as to perform a desired result.

In step 110, a geometric morphing device is formed according to abovedetermined design specifications in steps 100-108.

Referring now to FIG. 7, a logic flow diagram illustrating a method ofaltering the airfoil member 14 in accordance with an embodiment of thepresent invention is shown.

In step 120, a current vehicle state is determined including generationof vehicle performance signals. A vehicle operator command signal mayalso be generated including inceptor positioning. The controller 28determines a current vehicle state and a desired vehicle state inresponse to said vehicle performance signals and said operator commandsignals.

In step 122, the controller 28 in response to the current vehicle state,the desired vehicle state, and the vehicle performance signalsdetermines a desired state of the morphing device 30.

In step 124, the controller 28 compares a current state of the morphingdevice 30 with desired state of the morphing device 30 and alters sizeand shape of the morphing device 30, accordingly, to allow the aircraft10 to transition to the desired vehicle state. The controller 28 maycalculate fiber angles along a chord axis or a span axis to determinethe desired inflated state of the inflatable member 30, by using alook-up table relating inflated states to particular flight conditions,or by other methods known in the art. As inflated state is adjusted, byadjusting pressure within the inflatable member 30, fiber angles withinthe fiber mesh 34 are altered to adjust size, shape, span, chord, camberor a combination thereof. Resulting inflated stated provides propertorsion on components of the aircraft 10 for a current flight condition.

In one embodiment of the present invention, the controller 28 maydetermine internal pressure of the inflatable member 30 in response toairspeed, descent speed, and climb speed.

The controller 28 in determining pressures for the inflatable member 30may also determine the pressures in response to takeoff weight, angle ofattack, stall characteristics, or other aeronautical vehicle parametersknown in the art.

In another embodiment of the present invention in order to increasechord length of the morphing device 18 the controller 28 transitionsfrom a first inflated state to a second inflated state. The first statehaving a first chord length, a first span length, and a correspondingfirst pressured state. Pressure is adjusted in an inflatable member ofthe morphing device 18 to a second pressured state to alter the morphingdevice to have a second chord length that is greater than the firstchord length and a second span length that is less than a first spanlength.

The above-described steps in the above methods are meant to be anillustrative example, the steps may be performed synchronously,continuously, or in a different order depending upon the application.

Referring now to FIG. 8, a quarter cross-sectional view of a geometricmorphing device 18″″ including a single layer having an embedded fibermesh 130 in accordance with another embodiment of the present inventionis shown. The geometric morphing device has an inflatable member 30′″with an exterior wall 32′″. The exterior wall 32′″ has a single layer132 that includes an expandable member 134 and the fiber mesh 130embedded within the expandable member 134. The expandable member 134expands in response to changes in fiber angles 64′ of the fiber mesh130. The fiber mesh 130 is shown having a specific number of fiber 34′,fiber angles 64′, and a single fiber pattern 136, the fiber mesh mayhave any number of fibers, various fiber angles, and various fiberpatterns, similar to that of the above-described fiber meshes 34, 75,78, 81, 84, and 87. Although, in one embodiment of the present inventionthe expandable member 134 is formed of rubber and the fiber mesh 130 isformed of steel, the expandable member 134 and the fiber mesh 130 may beformed of other materials known in the art.

The simplified configuration of the exterior wall 32′″, in having asingle layer 132 is relatively less complex, simple to manufacture, andinexpensive. The reduced complexity of the configuration of the exteriorwall 32′″ provides ease in determining inflatable member distributionsand characteristics and response with change in internal pressure.

The present invention may be applied in a rotary aircraft, whereby aforward moving rotary blade has a different shape than a retreatingrotary blade, for improved lift distribution. The present invention mayalso be used to minimize rotor noise during dynamic operation.

The present invention may also be applied to a conard rotor wingaircraft to reverse an airfoil and increase or decrease span of a conardrotor to improve performance during a vertical lift mode or hover modeand during a fixed wing mode or cruise mode.

The present invention provides an airfoil member that is capable ofbeing significantly altered in size and shape to provide increaseperformance throughout one or more flight envelopes. The presentinvention is capable of improving performance of an aircraft at multipleflight speeds including at lower speeds by changing stall speed and liftof an airfoil member and at higher speeds by reducing drag whilemaintaining optimal lift.

The above-described apparatus and method, to one skilled in the art, iscapable of being adapted for various applications and systems known inthe art. The above-described invention can also be varied withoutdeviating from the true scope of the invention.

1. An airfoil member comprising: at least one geometric morphing devicecomprising: at least one inflatable member having at least one exteriorwall and a plurality of inflated states, said exterior wall having atleast one layer with at least one fiber embedded within said at leastone layer and controlling size, shape, and expansion ability of saidgeometric morphing device; said at least one geometric morphing deviceis adjustable in size and shape by changing inflated state of said atleast one inflatable member.
 2. An airfoil member as in claim 1 whereinfiber angles of said at least one fiber change in response to changes ininflated state of said at least one inflatable member altering shape ofsaid geometric morphing device.
 3. An airfoil member as in claim 1wherein said at least one layer comprises: at least one expandablemember; and said at least one fiber embedded within said at least oneexpandable member.
 4. An airfoil member as in claim 3 wherein said atleast one expandable member is formed of at least one elastomermaterial.
 5. An airfoil member as in claim 3 wherein said at least oneexpandable member is formed of rubber.
 6. An airfoil member as in claim1 wherein said at least one fiber is formed of steel.
 7. An airfoilmember as in claim 1 wherein said at least one layer comprises: at leastone expandable member; and a fiber mesh coupled to and embedded withinsaid at least one expandable member.
 8. An airfoil member as in claim 7wherein fiber angles of said fiber mesh change in response to changes ininflated state of said at least one inflatable member altering shape ofsaid geometric morphing device.
 9. An airfoil member as in claim 7wherein said fiber mesh is formed of steel.
 10. An airfoil member as inclaim 7 wherein said fiber mesh forms at least one fiber pattern.
 11. Anairfoil member as in claim 7 wherein said at least one expandable memberexpands in response to changes in fiber angles of said fiber mesh. 12.An airfoil member altering system for an airfoil member comprising: atleast one geometric morphing device comprising: at least one inflatablemember having at least one exterior wall and a plurality of inflatedstates, said exterior wall having at least one layer with at least onefiber embedded within said at least one layer and controlling size,shape, and expansion ability of said geometric morphing device; said atleast one geometric morphing device is adjustable in size and shape bychanging inflated state of said at least one inflatable member; at leastone vehicle performance characteristic sensor generating vehicleperformance signals; a pump fluidically coupled to said at least oneinflatable member; and a controller electrically coupled to said atleast one vehicle performance sensor and said pump and altering size andshape of said at least one geometric morphing device in response to saidvehicle performance signals.